Vernacular community centers in Hamadan city are known Chaman spaces. These spaces as local spaces not only standing for centuries and have not lost their significance but also gradually have achieved to valuable historical role and are invaluable in different perspectives. Chaman spaces are valuable in Specifications of cultural, religious, economic, urban development, traffic and climatically design. At first the necessity and importance of studying these spaces and useful results obtained from studying referred. One of the most important issues that show off face this spaces is special architecture of Chaman spaces. Every city which modern human life in, every day has a new aspect. As far as if after a few years away, come back to his native city, encounter with an unfamiliar face of the city. So cannot easily relationship this new mask with diary previous. Although, in some parts of the Hamadan historic city, dynamic community centers found that these urban living spaces designed in the base of human needs and behaviors. In Chaman space Physical comfort are supplied by the life-giving earth elements (water and plant), needs of Livelihood are provided with commercial applications and spiritual needs responded by religious and cultural spaces. These are important characteristics of community centers in Hamadan which in terms of common are known «Chaman». These spaces are part of the social and cultural identity of Hamadan. Chaman spaces and buildings around it is still a special place located at the nodes of the city and qualified values are a sign of a city. In Islamic culture, various aspects of the structure of vernacular community centers in Hamadan city is coordinated with Islam laws. How are vernacular community centers in Hamadan commitment to the ten principles of Islamic jurisprudence is the most research question: Reason as a tool of jurisprudence, fixing the principles, ramify details of general principles, Relativity in jurisprudence, Integrity all the rules, paying attention to all aspects of the human, according to priorities and expediencies, Harmony with the laws ruling, Full freedom in some areas, Five task orders, Secondary and governmental laws. The hypothesis of this research is: Vernacular community centers in Hamadan are outstanding example of Practical adherence to Islamic rules in Islamic architecture and urbanism of Iran. The aim of this research is Introducing the leading mode of examples manifestation of the principles of Islamic Iranian architecture and urbanism in local scale. So this research follows the proven correlation vernacular community centers in Hamadan as an example of Iran› s Islamic architectural with practice of Islamic laws. The system of this research is Historical interpretation and the strategy is correlation between vernacular community centers in Hamadan city and Islamic jurisprudence rules. The human base on Islam Have a fixed nature, so sustainability of these community centers in a long times shows harmony between communities with human necessities. Because of that answering to all human needs was paid attention. Response to the human physical dimension, the sense of sight with greenery, sense of hearing with sound of water and hearing the call to prayer, the sense of smell with the smell of flowers and the sense of touch to feel the breeze and air moisture and sense of taste with eating berries from the trees in these spaces respond. Response to the human Spiritual dimension also consider and provide with relaxation, social interaction, vitality and dynamism for the whole family. Finally, generally pattern and the structure used in the vernacular community centers in Hamadan will be presented. This pattern will provide solutions in designing the community centers with the Iranian Islamic model. Referral forms of pattern Chaman spaces will be efficient in maintenance and repair and revival of existing Islamic community center. The most important principles used in the vernacular community centers of Hamadan city that have been der ived from Islamic jurisprudence practical rules are: Gathering the essential needs of neighborhood residents, answering the environmental, cultural and economic needs of neighborhood residents, Priority to pedestrians on the roadway in the campus of community center, Respecting for the rights of neighbors with the building houses in the same heighten in the community and the lack of dominating on houses in the community, Responding to all aspects of human existence, Observing the hierarchy. Discover the pattern used in the body of lawn space can also be very efficient in providing design solutions for neighborhood open spaces.

The signs of the stability of each space are along with the dynamism over different generations. The neighborhood-centered system in Hamadan, Iran, represents dynamic neighborhoods over the years. Hamadan is composed of 50 neighborhoods possessing open squares in the center with markets and public spaces surrounding, named “Chaman” as the core of community in the best location to access urban nodes of several major passages, center of association, and social interactions of the neighborhood residents. In the urban texture from the Parthian period to the first Pahlavi, Hamadan has enjoyed the strongest and most dynamic center of neighborhoods that has consolidated the neighborhood-oriented system, having formed to respond to the existential dimensions of mankind and is a comprehensive supplier of residents` essential needs. Therefore, in addition to the Chaman space, this structure has cultural-religious and commercial spaces to meet the environmental, religious, and economic needs of residents. The archetype of Chaman can be restored as a model in accordance with Islamic culture and adapted to the climatic conditions in the city and in the design of new cities.The strategy used in this historical-interpretative research is based on the collection of information with library studies and field surveys. To conduct library studies, the repertoire of the research resource has been provided, including the general characteristics of the source, image, abstract, research process and referral cases. In order to conduct field studies, the physical identity repertoire has been set up in five physical, environmental, cultural, economic and cultural characteristic sections.Keywords: Hamadan, Chaman, Neighborhood Center, Square, Neighborhood Open space. IntroductionThe continuous change of the city’s image due to the ever-increasing development of the human being, after a few years away from birthplace, makes individuals so unfamiliar with that city that the past memories of the streets and alleys of the city are not associated at all. The same goes for the alternate changes in the principles of architecture and urbanization, and in particular the design of neighborhoods. Despite the current situation, in parts of the historical city of Hamadan, there are found neighborhoods preserving their Iranian-Islamic identity, representing a living space the design basis of which has been human, needs and behavior. The central area of the historical city of Hamadan has been formed from bordering and intermingling old neighborhoods, with the center of the neighborhood, which is the main identity of the neighborhood known as Chaman. Each of these in the past, there were about fifty neighborhoods in Hamadan, more than half of which had Chaman space.The identification of the model of Chaman space as a stable neighborhood pattern in achieving the open space design and modeling strategies in the design of new townships with neighborhood center-based structure and the introduction of templates and referral patterns for the reconstruction of the native neighborhood center are the objectives of this research.The Hypotheses of This Research are as Follows:  The Chaman is the dominant pattern of architecture and urbanization of the center of the native neighborhoods of Hamadan, which is an important physical space in the architecture and urbanization of Hamadan and the structure used in the center of Hamadan neighborhoods is of the most valuable historical urban structures in Iran. Therefore, some questioned are presented to be analyzed.What is the main structure of the center of the native neighborhoods of Hamadan? What role has the Chaman played in Hamadan historical texture? How valuable is Chaman in Hamadan’s native culture?Naming native open spaces of Hamadan has been seen in several sources with the following words: Chaman (Gharogozloo, 2009: 47), Square (Mehryar, 2008: 54), Neighborhood Center (Biglari, 1977: 58; Kiani, 1989) and field (Iran Housing Development, 1992).The Chaman includes the characteristics of the first three types of fields in the category of Zucker (Zucker, 1970); an enclosed field that is considered as a complete space and directed to the dominant element, which is the neighborhood mosque. This core field is formed mainly around the center in green space.  History of Hamadan NeighborhoodsHamadan city is located in the Alvand mountain zone in Iran. It is located at 1741.5 M and 34 52 N and 48 32 E. Formation of Hamadan Neighborhood Before IslamThe dominant feature of Hamadan has been the existence of numerous gardens and fountains reflecting the formation of neighborhoods semen based on water and trees. It seems that during this period, the bazaar was added as one of the main elements of the neighborhoods, which flourished in the Islamic period. The Prosperity and Flourishing of Hamadan Neighborhoods: The Islamic PeriodBecause of the sanctity, the mosques are the most important element remained as the center of the Hamadan neighborhoods and make it easy to recognize the location of the forgotten neighborhoods. Evidence suggests that these mosques were constructed in the neighborhoods of the city after the Safavid period. (Zarei, 2011: 70) Regarding the numerous number of neighbors, it can be said that the flourishing era of Chaman space and neighborhood structure in Hamadan was the late Qajar.  Terminology of ChamanIn a comprehensive definition of the Chaman space, considering the structure and the physical elements and social, economic and environmental characteristics. The field Chaman is enclosed with a geometric form in the core of the neighborhood with the best access location, which is the communicative node of several important urban centers, the center of gathering and a social intermediary community that meets the needs of the people with the necessary uses including mosques, baths, marketplaces, and water and plant elements. Hosseinieh, Imamzadeh and Saghakhaneh are among the most common cultural spaces around Chaman, and bakery, butchers, groceries and small manufacturing factories such as shoe and carpentry are the most popular. ConclusionKnown as the center of neighborhood, green closed Square, the neighborhood open space is recognized in Hamadan as Chaman.The history mentioned for the Chaman spaces as the center of the green and historical neighborhoods of Hamadan dates back to the time of the Parthians (the third century BC) and still in the sixth and seventeenth century the Hamadan neighborhoods were mentioned. In the Safavid era, besides the bath and market, the mosques are also the main elements of the structure of the Chaman spaces and added to the important elements of the market during the Qajar era. Evidence suggests that the years 1871 to 1921 (the late Qajar) experienced the peak and flourishing years of Hamadan neighborhood when the number of neighborhoods in the main structure of the city reached 51.The identification of 51 neighborhoods before the 1945th Lunar years and then the introduction of 42 neighborhoods after about seventy years in 1973 and eventually taking into account the 25 existing or damaged neighborhoods in the next twenty years in 1992, shows the process of demolition and destruction of the Hamadan neighborhoods by the streets. This trend tend to continue, as there are now a handful of originality neighborhoods. The word “Chaman”, is the prefix of the center of Hamadan neighborhoods, and at least the name of 13 neighborhoods registered with that prefix, has a place, definition and value in the indigenous culture of Hamadan.

Studied amphibolites are located in South West Chaman Soltan, in central parts of the Sanandaj-Sirjan structural zone. Geochemical data of the amphibolites show that their protolith are tholeiitic basalts with an affinity of enriched MORB (E-MORB) type that have formed in ocean floor setting. The rocks have undergone the alteration by seawater. After metamorphism, these rocks as amphibolite have emplaced during the orogenic processes in present tectonic setting.

It is henceforth a commonplace; the science-fiction would be a refractory genre by nature against the definitive assimilation to the literary mainstream. We can say that the usual thematic of the genre, to which is added the irresistible propensity to prospect the future in all its forms, immunizes the SF against the “academic confinement” to the benefit of other forms of confinement. Indeed, the SF belongs to the great family of the paraliterature where the more or less listed subgenres are waiting to receive a likely definition. Popular genre which relies on a remarkable poetic, the SF is an open place to the imagination, to the verbal and the figurative creativity. It owns itself its subgenres, among other things, the space opera which was, in a way, the original matrix of the speculative fiction and of its contemporary imitators. The Sternberg’s work did not have a special vocation to feed the already rich world of the science-fiction. It constitutes however a new step liable to bring a touch of self-reflexivity, we will notice that, to the history of this genre. French: “Le Navigateur” de Jacques Sternberg ou la phylogenese parodiee du space opera C’est dorenavant un lieu commun, la science-fiction serait un genre par nature refractaire a l’assimilation definitive au mainstream litteraire. Nous dirons que les thematiques habituelles du genre, auxquelles viennent se meler l’irresistible propension a prospecter l’avenir sous toutes ses formes, immunisent la SF contre “l’enfermement academique” au profit d’un enfermement d’un autre genre. En effet, celle-ci appartient, comme on le sait, a la grande famille de la paralitterature ou se cotoient les sous-genres plus ou moins repertories en attente de recevoir un semblant de definition. Genre populaire s’appuyant sur une poetique singuliere, la SF est un lieu ouvert a l’imagination, a la creativite verbale et figurative. Elle possede elle-meme ses sous-genres, entre autres, le space opera qui fut en quelque sorte la matrice originelle de la fiction speculative et de ses emules contemporaines. L’oeuvre sternbergienne n’eut guere pour vocation de nourrir le repertoire deja riche de la science-fiction. Elle constitue neanmoins une etape non repertoriee susceptible d’apporter, nous le constaterons, une touche d’auto-reflexivite a l’histoire du genre.Keywords: Jacques Sternberg, Nouvelle, Science-Fiction, space Opera, Aventure, Fiction Speculative

Background: Cement space is necessary for seatabillity and fitness of cast crowns, but can affect crown's retention. In this study the interrelationship between them was investigated via die spacing.Materials and Method: For evaluating the effect of die spacing (cement space) on crown retention after cementation, 50 similar machined metallic dies were prepared and divided into five groups and coated with 0.2, 4, 6, 8 layers of paint-on standard die spacer, respectively. Cast crowns. Were fabricated on the dies using base metal alloys, and then cemented with zinc phosphate cement under a constant load of 5kg for 10 minutes. The samples were started in distilled water for 48 hours. Then the force required to remove each crown from the die was measured with instron.Results: Statistical analysis revealed a significant increase in the force required (crown retention) by adding layers of die spacer (p<0.05).Conclusion: Because retention didn't show any significant increase with more than 4 layers of die spacer, so optimum thickness of die spacer (or cement space produced) is suggested to be 4 layers equal to 40 microns.

The type section of the Middle and Upper Jurassic Chaman Bid Formation is in the western Koppeh-Dagh Basin (Northeast Iran). It is unusually thick and contains a rather rich ammonite fauna, ranging from Bathonian to Tithonian. The ammonites described here come from a 134-m-thick interval in the upper part of member (D) in the middle part of the formation, consisting of an alternation of grey limestone and marly limestone. The following ammonite families are present: Haploceratidae, Oppeliidae, Perisphinctidae, and Ataxioceratidae, among them the following taxa have being recorded for the first time from Iran: Phanerostephanus subsenex, Phanerostephanusaff. intermedius, Nothostephanus aff. kurdistanensis, Nannostephanus cf. subcomutus and Oxylenticeras cf. lepidum. This assemblage is belonging to the Lower Tithonian Semiforme Zone or even older zones. The Fallauxi Zone is represented byRichteria richteri.

As a result of the influence of the Persian language and literature on the Indian subcontinent and generous protection of the Indian kings from the Persian writers and poets, a great deal of works have been written in that territory including the book, Chahar-Chaman written by Chandarbahan Brahman, so called as ‘the Persian-knowing Hindu’.His complete works include lyric poems and quatrains. One of his most important works is Chahar-Chaman, a literary and historical work written in four chapters each of which is entitled ‘Chaman’. His language in poetry is simple and his poems contain concepts such as love, affection, Sufism and unity of existence which have been composed in a mystic tone.In the present research paper, in addition to providing a brief biography of Chandarbahan Brahman, we have attempted to study the most outstanding points of his book, Chahar-Chaman, and to show its significance and value.

Purpose: The aim of this study was to compare the effects of A) a flame heated endo plugger, B) GatesGlidden drills and C) GPX drills on the apical seal for the purpose of post space preparation. Materials & Methods: The crowns of sixty six extracted maxillary central teeth were removed from CEJ by a diamond disc and the root canals were prepared and obturated with guttapercha and sealer (Ah26) using lateral condensation technique. Six teeth were used as positve and negative control groups and the other sixty teeth were divided into 3 groups, each group containing 20 teeth. The post space in these 3 groups was made by either A/a hot plugger, B/# 3or# 4 Gates glidden drills and C/# 40 or # 50 GPX drills and apical dye leakage in each group was measured by stereomicroscope and the Anova test was used to compare the mean amount of dye leakage between groups.Results: Between these 3 groups, the minimal mean dye leakage was related to the hot plugger group and the maximum mean leakage was observed in Gates glidden drill group. There was significant statistical difference between the groups (P=0.005).Conclusion: The GPX drills for the purpose of post space preparation affect apical seal less than Gates glidden drills.